Surface treating appliances such as vacuum cleaners and floor polishers are well known. The majority of vacuum cleaners are either of the ‘upright’ type or of the ‘cylinder’ type, called canister or barrel cleaners in some countries. A typical upright vacuum cleaner comprises a main body which houses the main components of the vacuum cleaner, such as a motor and fan for drawing dirty air into the machine and some form of separating apparatus for separating dirt, dust and other debris from a dirty airflow drawn in by the fan. The main body also houses filters for trapping fine particles in the cleaned airflow. A cleaner head is rotatably mounted to the lower end of the main body. A supporting wheel is mounted on each side of the lower part of the main body, in a fixed relationship to the main body. In use, a user reclines the main body of the vacuum cleaner and then pushes and pulls a handle which is fixed to the main body of the cleaner. The vacuum cleaner rolls along the floor surface on the supporting wheels.
A dirty-air inlet is located on the underside of the cleaner head. Dirty air is drawn into the dust separating apparatus via the dirty-air inlet by means of the motor-driven fan. When the dirt and dust entrained within the air has been separated from the airflow in the separating apparatus, air is conducted to the clean air outlet by a second air flow duct, and via one or more filters, and expelled into the atmosphere.
Conventional upright vacuum cleaners have a disadvantage in that they can be difficult to manoeuvre about an area in which they are used. They can be pushed and pulled easily enough, but pointing the cleaner in a new direction is more difficult. It has been proposed to make an upright vacuum cleaner more manoeuvrable by substituting a wide rolling support for the supporting wheels, such as is described in our patent application GB2422094. A support assembly is provided to give further support to the main body when in the vertical position. The support assembly is moveable between a supporting position, in which it supports the main body of the appliance, and a stored position, in which it lies substantially against the main body. The support assembly is released from its supporting position by a user-operable foot pedal.
A problem which may be encountered with this type of support assembly is that there is a risk of inadvertent release of the support assembly from its supporting position. For example, if the user accidentally depresses the pedal, or if an object falls on it, the support assembly is brought out of its supporting position. Without the support of the support assembly, the main body has a tendency to tilt backwards and thus the appliance might topple over.